A crane with an erectable jib is known from CN 102 745 604 A. The jib is swivel-mounted on an upper carriage of the crane in a foot area. The jib is connected with an erection device, actuated by means of a rope reeving, in a head area for erecting the same. Related to an axis of rotation of a rotary connection arranged between the upper carriage and the under carriage of the crane the linkage of the jib is off centre. An anchoring rod is bolted to bores between the upper carriage and the under carriage envisaged for this in order to avoid an undesired load on the rotary connection. The anchoring rod enables a direct introduction of tensile forces from the upper carriage into the under carriage when the jig is erected. The anchoring rod requires high dimensional accuracy in order to guarantee that the bolting of the anchoring rod to the upper carriage and the under carriage is possible without difficulty. Fitting the anchoring rod at the specifically stipulated distance from installation openings is problematic in particular when a counterweight is arranged on the upper carriage, which for example varies depending on the jib to be erected.
DE 35 31 291 A1 discloses a supporting swing jib crane with a rotary platform which is rotatable on a track of a foundation by means of supporting rollers. Vertical forces occurring as a consequence of dropping load are transmitted by the rollers to the track.
DE 28 44 819 A1 discloses a mobile crane for heavy loads. An upper carriage, with an intermediate frame and load roller arranged thereon, is vertically positively driven between a track ring and a frame.
A crane with an erectable jib is known from DE 10 2011 119 655 A1. An actively length-adjustable hydraulic cylinder is envisaged as a force-limited connection element in order to take the load off the reel connection between the upper carriage and the under carriage. An active hydraulic cylinder is comparatively heavy, in particular compared to an anchoring rod, needs to be controlled or regulated, is prone to faults, cost intensive and maintenance intensive. An active hydraulic cylinder also requires a complex hydraulic supply.